1. Field of the Invention
The present invention provides a nitride-based light-emitting device and a method for manufacturing the same, and more particularly, a nitride-based light-emitting device with a ternary nitride-based buffer layer.
2. Description of the Prior Art
The applications of light-emitting diodes are extensive and include optical display devices, traffic signals, data storing devices, communication devices, illumination devices, and medical apparatuses. As such, it is important to increase the brightness of light-emitting diodes, and to simplify manufacturing processes in order to decrease the cost of the light-emitting diode.
In general, a prior art nitride-based light-emitting device includes a nitride-based buffer layer of group AlGalnN formed over a sapphire substrate, and undergoes a nitride-based epitaxy process on the nitride-based buffer layer. Due to problems associated with the matching of crystal lattice constants, dislocation density (which affects quality of the prior art nitride-based light-emitting device), cannot be decreased efficiently. Therefore, the prior art nitride-based epitaxy process seeks to increase the quality of the prior art nitride-based light-emitting device with a two-step growth method, which utilizes low-temperature (500˜600° C.) GaN for forming a buffer layer, a heating process (reaching a temperature of 1000˜1200° C.) for effecting crystallization, and an epitaxy process for each epitaxy stack layer. The thickness and temperature of the buffer layer, recovery of the heating and re-crystallization processes, plus the ratio and flow rate of gas for each reaction must be controlled precisely, thus making the production process complex and difficult, and as a consequence production efficiency cannot be increased.